The present invention relates generally to techniques for connecting a plurality of pieces of sound equipment to cause the connected pieces of equipment to function together as a single unit.
In the field of speaker array systems each comprising a plurality of speaker units, there has been known a technique for imparting a sound signal with time delays corresponding to phase differences and providing the resultant delayed sound signals to the individual speakers such that the signals agree in phase only at a desired position (focal point) to which the sound is to be conveyed, so as to form a high sound pressure region (i.e., sound beam) extending toward the focal point or a spot-shaped high sound pressure region (i.e., sound spot) produced at and around the focal point (e.g., Japanese Patent Application Laid-open Publication No. HEI-06-205496 which corresponds to U.S. Pat. No, 5,953,432). Further, in the field of microphone array systems each comprising a plurality of microphone units, there has been known a technique for identifying a sound generation source (sound image localization) on the basis of phase differences and intensity differences of sounds input to the individual microphones, or for separating a plurality of sounds (sound source separation). In each of the above-mentioned techniques, it is necessary to provide a plurality of pieces of sound equipment (speaker units or microphone units).
However, in a speaker array system with a small number of speaker units, there would arise the problems that only a low degree of freedom is permitted as regards positions to localize sound images and directivities of the speakers and that a range of frequencies of produceable sound beams is limited. Namely, in order to achieve an enhanced degree of freedom as regards sound image localization positions and expanded frequency bands of produceable sound beams, it is necessary to increase the number of the speaker units to be provided. However, the increase in the number of the speaker units unavoidably leads to an increased size of the entire apparatus, so that the installing location of the apparatus may be limited and transport of the apparatus may be hindered.
Among conceivable solutions to the aforementioned problems is to juxtapose ten speaker arrays, each comprising ten speaker units, instead of using 100 speaker units. However, merely juxtaposing the plurality of speaker arrays can not allow these speaker arrays to together function as if they were a single speaker array, because, in this case, the speaker arrays only operate independently of each other. In order for the entire set of the speaker arrays to perform a unified function, some correlation, corresponding to operational contents (sound effects), has to be established in advance between timing of sound signal processing to be performed by each of the speaker arrays and timing of sound signal processing to be performed by the other speaker arrays.